package de.rwu.easydrop.api.client;

import java.net.MalformedURLException;
import java.net.URL;

import com.jayway.jsonpath.JsonPath;
import com.jayway.jsonpath.PathNotFoundException;
import com.jayway.jsonpath.ReadContext;

import de.rwu.easydrop.api.dto.ProductDTO;

/**
 * Interface to an eBay data source.
 *
 * @since 0.2.0
 */
public final class EbayItemDataSource extends AbstractDataSource {
    /**
     * Name of this data source.
     */
    private static final String DATA_ORIGIN = "eBay";
    /**
     * Base URL to the eBay data source.
     */
    private String baseUrl;
    /**
     * Credential key to authorize access.
     */
    private String apiKey;

    /**
     * Sets up instance with Base URL and API Key.
     *
     * @param newBaseUrl
     * @param newApiKey
     */
    public EbayItemDataSource(final String newBaseUrl, final String newApiKey) {
        this.baseUrl = newBaseUrl;
        this.apiKey = newApiKey;
    }

    /**
     * @param searchQuery Exact product name or other valid identifier.
     */
    @Override
    public URL createApiUrl(final String searchQuery) throws MalformedURLException {
        return new URL(baseUrl
                + "/buy/browse/v1/item_summary/search?q="
                + searchQuery
                + "&limit=1&offset=0");
    }

    /**
     * Enriches a ProductDTO with API-gathered data.
     *
     * @param product Unfinished ProductDTO
     * @param json    Product data
     * @return Finished ProductDTO
     */
    public ProductDTO buildProductDTO(final ProductDTO product, final String json) {
        String root = "$.itemSummaries[0].";
        ReadContext ctx = JsonPath.parse(json);

        try {
            product.setDataOrigin(DATA_ORIGIN);
            product.setAvailable(
                    ctx.read(root + "shippingOptions[0].guaranteedDelivery", boolean.class));
            product.setCurrentPrice(ctx.read(root + "price.value", double.class));
            product.setDeliveryPrice(
                    ctx.read(root + "shippingOptions[0].shippingCost.value", double.class));
            product.setMerchant(ctx.read(root + "seller.username", String.class));
        } catch (PathNotFoundException e) {
            // Pass, allow incomplete ProductDTO to pass for later validation
        }

        return product;
    }

    @Override
    protected String getDataOrigin() {
        return DATA_ORIGIN;
    }

    @Override
    protected String getApiKey() {
        return this.apiKey;
    }
}